Whatever you fix, it'll only be temporary.

When driving 400W speakers from a 1000W amp, you have 250% more power than the speakers can handle.

So start taking bets as to how long the repair will last until something blows again because the power levels are simply too high.... 2 days? 1 week? 1 month?

If you want reliability, then make sure the components are rated with appropriate power handling levels...... and always use speakers rated for more than the amp can produce.